The 107″ telescope at McDonald observatory in Texas has been around since 1968 and has is still in operation to this day, despite bullet holes in its primary mirror!
https://en.wikipedia.org/wiki/Harlan_J._Smith_Telescope

The 107″ telescope at McDonald observatory in Texas has been around since 1968 and has is still in operation to this day, despite bullet holes in its primary mirror!
https://en.wikipedia.org/wiki/Harlan_J._Smith_Telescope